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. 2016 Sep 16;8(2):202–212. doi: 10.1002/jcsm.12145

Figure 2.

Figure 2

Activin A up‐regulates the expression of E3 ubiquitin ligases UBR2 and atrogin1 through the activation of p38β MAPK in C2C12 myotubes. (A) Activin A up‐regulates UBR2 and atrogin1 via p38 MAPK. C2C12 myotubes were treated with activin A with or without the presence of SB202190 for 8 h. Cell lysate was analysed by Western blotting. (B) JNK inhibition does not affect activin A up‐regulation of UBR2 and atrogin1. (C) Activin A up‐regulates UBR2 and atrogin1 via p38β MAPK. C2C12 myoblasts transfected with small interfering RNA (siRNA) as indicated were differentiated for 96 h to form myotubes and then treated with activin A for 8 h. E3 levels in cell lysate were determined by Western blotting. (D) Activin A up‐regulates UBR2 and atrogin1 gene expression via p38 MAPK. C2C12 myotubes were treated as described in (A) for 4 h. Real‐time PCR was performed to determine mRNA levels of the two genes. (E) Activin A up‐regulation of the UBR2 and atrogin1 gene requires p38β MAPK. C2C12 myoblasts transfected with siRNA as indicated were differentiated for 96 h to form myotubes and then treated with activin A for 4 h. Real‐time PCR was performed to determine mRNA levels of the two genes. Data were analysed with analysis of variance. Asterisk (*) denotes a difference (P < 0.05).